export RQ status as prometheus metrics

fixes: rq#503

django_rq/metrics_collector.py

@@ -0,0 +1,59 @@
+from rq.job import JobStatus
+
+from .queues import filter_connection_params, get_connection, get_queue, get_unique_connection_configs
+from .workers import get_worker_class
+
+try:
+    from prometheus_client import Summary
+    from prometheus_client.core import GaugeMetricFamily, CounterMetricFamily
+
+    class RQCollector:
+        """RQ stats collector"""
+
+        summary = Summary('rq_request_processing_seconds', 'Time spent collecting RQ data')
+
+        def collect(self):
+            from .settings import QUEUES
+
+            with self.summary.time():
+                rq_workers = GaugeMetricFamily('rq_workers', 'RQ workers', labels=['name', 'state', 'queues'])
+                rq_workers_success = CounterMetricFamily('rq_workers_success', 'RQ workers success count', labels=['name', 'queues'])
+                rq_workers_failed = CounterMetricFamily('rq_workers_failed', 'RQ workers fail count', labels=['name', 'queues'])
+                rq_workers_working_time = CounterMetricFamily('rq_workers_working_time', 'RQ workers spent seconds', labels=['name', 'queues'])
+
+                rq_jobs = GaugeMetricFamily('rq_jobs', 'RQ jobs by state', labels=['queue', 'status'])
+
+                worker_class = get_worker_class()
+                unique_configs = get_unique_connection_configs()
+                connections = {}
+                for queue_name, config in QUEUES.items():
+                    index = unique_configs.index(filter_connection_params(config))
+                    if index not in connections:
+                        connections[index] = connection = get_connection(queue_name)
+
+                        for worker in worker_class.all(connection):
+                            name = worker.name
+                            label_queues = ','.join(worker.queue_names())
+                            rq_workers.add_metric([name, worker.get_state(), label_queues], 1)
+                            rq_workers_success.add_metric([name, label_queues], worker.successful_job_count)
+                            rq_workers_failed.add_metric([name, label_queues], worker.failed_job_count)
+                            rq_workers_working_time.add_metric([name, label_queues], worker.total_working_time)
+                    else:
+                        connection = connections[index]
+
+                    queue = get_queue(queue_name, connection=connection)
+                    rq_jobs.add_metric([queue_name, JobStatus.QUEUED], queue.count)
+                    rq_jobs.add_metric([queue_name, JobStatus.STARTED], queue.started_job_registry.count)
+                    rq_jobs.add_metric([queue_name, JobStatus.FINISHED], queue.finished_job_registry.count)
+                    rq_jobs.add_metric([queue_name, JobStatus.FAILED], queue.failed_job_registry.count)
+                    rq_jobs.add_metric([queue_name, JobStatus.DEFERRED], queue.deferred_job_registry.count)
+                    rq_jobs.add_metric([queue_name, JobStatus.SCHEDULED], queue.scheduled_job_registry.count)
+
+                yield rq_workers
+                yield rq_workers_success
+                yield rq_workers_failed
+                yield rq_workers_working_time
+                yield rq_jobs
+
+except ImportError:
+    RQCollector = None

django_rq/urls.py

@@ -1,10 +1,16 @@
 from django.urls import re_path
 
 from . import views
+from .metrics_collector import RQCollector
+
+metrics_view = [
+    re_path(r'^metrics/?$', views.prometheus_metrics, name='rq_metrics'),
+] if RQCollector else []
 
 urlpatterns = [
     re_path(r'^$', views.stats, name='rq_home'),
     re_path(r'^stats.json/(?P<token>[\w]+)?/?$', views.stats_json, name='rq_home_json'),
+    *metrics_view,
     re_path(r'^queues/(?P<queue_index>[\d]+)/$', views.jobs, name='rq_jobs'),
     re_path(r'^workers/(?P<queue_index>[\d]+)/$', views.workers, name='rq_workers'),
     re_path(r'^workers/(?P<queue_index>[\d]+)/(?P<key>[-\w\.\:\$]+)/$', views.worker_details, name='rq_worker_details'),

django_rq/views.py

@@ -5,7 +5,7 @@
 
 from django.contrib import admin, messages
 from django.contrib.admin.views.decorators import staff_member_required
-from django.http import Http404, JsonResponse
+from django.http import Http404, HttpResponse, JsonResponse
 from django.shortcuts import redirect, render
 from django.urls import reverse
 from django.views.decorators.cache import never_cache
@@ -28,6 +28,15 @@
 from .settings import API_TOKEN, QUEUES_MAP
 from .utils import get_executions, get_jobs, get_scheduler_statistics, get_statistics, stop_jobs
 
+try:
+    import prometheus_client
+
+    from .metrics_collector import RQCollector
+except ImportError:
+    prometheus_client = RQCollector = None
+
+registry = None
+
 
 @never_cache
 @staff_member_required
@@ -49,6 +58,25 @@ def stats_json(request, token=None):
     )
 
 
+@never_cache
+@staff_member_required
+def prometheus_metrics(request):
+    global registry
+
+    if not RQCollector:
+        raise Http404
+
+    if not registry:
+        registry = prometheus_client.CollectorRegistry(auto_describe=True)
+        registry.register(RQCollector())
+
+    encoder, content_type = prometheus_client.exposition.choose_encoder(request.META.get('HTTP_ACCEPT', ''))
+    if 'name[]' in request.GET:
+        registry = registry.restricted_registry(request.GET.getlist('name[]'))
+
+    return HttpResponse(encoder(registry), headers={'Content-Type': content_type})
+
+
 @never_cache
 @staff_member_required
 def jobs(request, queue_index):

setup.py

@@ -19,6 +19,7 @@
     },
     install_requires=['django>=3.2', 'rq>=2', 'redis>=3.5'],
     extras_require={
+        'prometheus-metrics': ['prometheus_client>=0.4.0'],
         'Sentry': ['sentry-sdk>=1.0.0'],
         'testing': [],
     },